Speaking from my own personal experience, I feel that the only way to think it's fair to say that most everyone has hundreds of magazines stacking up is if one were to count their personal copies from over the years. I (like various others I've known) like to have both bound volumes and personal copies in my library. The bound volumes are kept clean, for photocopying from or for letting others use; the personal ones are marked from cover to cover in 4-color pen — both underlining in the paragraphs, and marginal notes; both from personal study and from congregational study. I still do it that way, even though I've been df'd for 14 months now. I'm still regular as clockwork, and am always one of the first to go to the mag counter.
There certainly have been lots of announcements, especially in the years past, for people to regularly adjust their orders at the magazine counter. And if the placement mags were starting to stack a little, there might be suggestions at the service groups, etc. to encourage street witnessing, which was always a great way to find a way to place, especially if a person had a mag route and lots of RVs and Bible Studies, which I knew how to do years ago.
Along that line, I remember 10 years ago, when I was still allowed to publish, that several in the downtown congregation I was in had standing orders of 20-25 of both Watchtower and Awake!, and we were constantly running empty and having to ask one another, or get the brothers to make an announcement to bring mags in from home. Sometimes there'd be none that anyone could find, and we'd be asking for more from other congregations around. But then we had a fairly large shift-work/immigrant population, with a large number of foreign language mags. Many of them were trying to learn English, so they'd take both their native language (if it was available) and in English, and compare wording. Those certainly were the days! By now things are much tamer, not the rivalry there once was. Galatians 6:4 is a staple now, in that department. Every once in a while, though, a person will hear an (assembly) experience of someone placing 75 books at work, or some such, but it has to be pretty extraordinary like that for the numbers to come out, generally.